Actively exploited · Published Jan 13, 2026 · Assigned by fortinet
CVE-2025-25249
High 7.4 Exploited
In plain English
A high-severity heap buffer overflow in FortiOS from Fortinet. Attackers are actively exploiting it in the wild (listed by CISA on September 9, 2026). The chance it is exploited in the next 30 days is estimated at 3.7% (higher than 90% of all known vulnerabilities). Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA guidance
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Federal agencies must remediate by Sep 12, 2026.
Official description
A heap-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11, FortiOS 7.0.0 through 7.0.17, FortiOS 6.4 all versions, FortiSwitchManager 7.2.0 through 7.2.6, FortiSwitchManager 7.0.0 through 7.0.5 allows attacker to execute unauthorized code or commands via specially crafted packets
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Fortinet | FortiSwitchManager | 7.2.2 – through 7.2.5 |
| Fortinet | FortiOS | 7.6.0 – through 7.6.27.4.0 – through 7.4.77.2.4 – through 7.2.11 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:W/RC:C
References
- https://fortiguard.fortinet.com/psirt/FG-IR-25-084
- https://socradar.io/blog/cve-2025-25249-pivotc2-fortigate-rat/ third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-25249 government-resource
- https://cert-portal.siemens.com/productcert/html/ssa-864900.html